Port `chromium` wrapper logging to `firefox`
Port `chromium` wrapper logging to `firefox`

If `$browser_debug` is non-empty, log the arguments and process tree to
`~/browser.log`.  (Updated old `firefox` debugging to match newly-added
`chromium` logic.)

benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles